Cutting the Grass: How Short is Too Short?

How Short Should You Cut Your Grass?

It’s rarely a mystery when a lawn is getting too long and needs to be trimmed. However, what height should you cut your grass to keep it green and healthy?

This article was originally posted on WCCO/CBS Minnesota’s website and was written by John Lauritsen. You can read it in its original context here.

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Homeowners are hustling to get their lawns mowed after a reprieve from the rain.

Lots of us probably think shorter is better, but experts say that is not the case.

“Our cool-season grasses are growing so much right now just based on the weather we’ve been having,” said Sam Bauer, a turf grass educator with the University of Minnesota Extension.

He says cutting your grass too short, especially this time of year, puts significant stress on your lawn.

“With crab grass pressures in the spring of the year, mowing short can reduce the density of the lawn and that’s opportunity for crab grass to come in and take over,” Bauer said.

That means less root growth, with more fertilizer and water required. So what is the magic number?

“Three, 3-and-a-half [inches],” Bauer said. “About the highest that your home lawn mowers, the little walk-behind mowers will go is 3-and-a-half or 4 inches.”

Bauer recommends implementing what’s called the “one-third rule” with your lawn.

“It basically states that, you know, do not cut off any more than one-third of your lawn at any one mowing,” he said. “So if you’re mowing height is 3 inches, you can let it grow to 4-and-a-half inches. Cut off an inch and a half and then you’re back to 3 inches.”

Bauer says letting your grass grow just a little longer could make you the envy of the neighborhood.

“Your lawn’s really going to thank you for it,” Bauer said. “You’ll have less weeds because of it as well. And you’re just going to have a healthier, more robust root system.”

He says there is such a thing as letting your grass grow too much.

Voles, mice and snakes can start to move into your lawn when it starts to get over five inches.